jacket Definition

1. A short coat, especially a long-sleeved, hip-length one.

Thesaurus: coat, tunic, parka, mackinaw (US).
2. Something worn over the top half of the body.

Example: life jacket
3. A dust jacket.
4a. An outer casing for a boiler, etc, for preventing heat loss;
4b. Any protective casing.

Thesaurus: sheath, shell, envelope, wrap.
5. The skin of a potato that has been cooked without being peeled.